This application claims priority under 35 USC 119(a) to Patent Application No. 2004-063739 filed in Japan on 8 Mar., 2004, the content of which is hereby incorporated herein by reference in its entirety.
The Invention relates to a sensor system comprising a sensor apparatus represented by, for example, a microwave sensor (hereinafter referred to as a “MW sensor”), and a sensor apparatus used in the sensor system and a reception apparatus used in combination with the sensor apparatus. Especially, the invention relates to a solution for enabling a sensing area of the sensor apparatus to be checked easily and accurately.
Conventionally, as one of sensors used as a security apparatus and the like, a MW sensor is known for transmitting microwaves to a detection area (a monitoring area) and, if a human body (an detection target object) exits in the detection area, receiving reflected waves from the human body (microwaves modulated by the Doppler effect) to detect the human body (an intruder) (e.g., Japanese Patent Application Laid-Open Publication No. 2003-207462).
Also, this type of the MW sensor may be used in combination with a PIR sensor receiving infrared radiations from a human body within the detection area to detect the intruder from a difference between a temperature of the human body and an ambient temperature (e.g., Japanese Patent Application Laid-Open Publication No. 2002-55173). In other words, by overlapping the detection area of the MW sensor and the detection area of the RIP sensor and by obtaining the AND of both detected counts, weaknesses of the both sensors are complemented and the credibility is enhanced against causes of false alerts. As used herein, the weaknesses of the both sensors can be cited as false alerts in the MW sensor due to effects of external electric waves and false reports in the PIR sensor due to effects of sunlight and the like. Specifically, a beam range (a range where infrared radiations from a human body can be received) of the PIR sensor is set up off the ground and, thereby, the detection area and the non-detection area are partitioned. Therefore, when a large object (e.g., a cargo truck or a train) passes through the vicinity of the combination sensor and is detected by the MW sensor (the MW sensor generates an alert), if the object is located outside of the detection area set by the PIR sensor (outside of the beam range), the combination sensor can considers that the object is not detected (an alert is not generated).
By the way, in installation operations for the MW sensor, by setting sensing areas of the sensors to be desired areas, installation must be done such that human bodies are not recognized in areas not required to be monitored, in other words, such that human bodies are accurately recognized in areas required to be monitored. Therefore, after installing the MW sensor, an operation must be performed for checking the sensing area. For traditional checking operations, a MW sensor has been provided with a light-emitting unit for emitting lights or a speaker for making sounds, and after installing the sensor, an operator has been walking around an area thought to be the sensing area, has checked emissions of lights or sounds from the MW sensor and has determined whether the point of the operator has been set as the sensing area or not (whether the point has been included in the area where a human body can be detected by the MW sensor).
However, these checking operations have problems stated below.
First, in the case of the sensor with the light-emitting unit for emitting lights when a human body is detected, if the MW sensor is installed outdoor, a light-emitting status of the light-emitting unit is difficult to be identified in daytime checking operations, and especially if the sensing area is extensively defined (for example, if the sensing area is defined up to a point 100 m away from the MW sensor installation point), the light-emitting status of the light-emitting unit is almost impossible to be checked with eyes of the operator since a distance between the operator and the sensor is too far. Although, in order to easily check the light-emitting status with eyes, a large light-emitting unit must be provided or an amount of the emission must be increased, this can cause troubles such that the design of the MW sensor is adversely affected or that power consumption of a built-in battery is increased.
Also, in the case of the sensor with the speaker, if the sensing area is extensively defined, sounds from the speaker is difficult to be heard by the operator since a distance between the operator and the sensor is too far. Although, in order to here the sounds from the speaker easily, the sounds from the speaker must be set louder, this can cause troubles such that the power consumption of the built-in battery is increased as above, as well as that noise problems occur.
As a solution for these troubles, one can consider to locate an operator for checking the emission of lights or generation of sounds in the vicinity of the MW sensor, however, in this way, not only multiple operators are required, but also operations become complicated since the operators must check the sensing area while talking with each other by equipments such as transceivers.
These problems are posed not only when the MW sensor is used independently, but also the combination sensor described above is used. In other words, for the combination sensor, the check must be done for the sensing area of the MW sensor and the sensing area of the PIR sensor, and the same problems as above are generated in these checking operation. Also, this is not limited to the case that the microwave sensor and infrared radiations are used, and the same applies to sensors using other sensing signal waves.